Antifungal Activity against Botrytis cinerea of 2,6-Dimethoxy-4-(phenylimino)cyclohexa-2,5-dienone Derivatives.

In this work the enzyme laccase from Trametes versicolor was used to synthetize 2,6-dimethoxy-4-(phenylimino)cyclohexa-2,5-dienone derivatives. Ten products with different substitutions in the aromatic ring were synthetized and characterized using ¹H- and 13C-NMR and mass spectrometry. The 3,5-dichlorinated compound showed highest antifungal activity against the phytopathogen Botrytis cinerea, while the p-methoxylated compound had the lowest activity; however, the antifungal activity of the products was higher than the activity of the substrates of the reactions. Finally, the results suggested that these compounds produced damage in the fungal cell wall.

Temporal Variation of Aristolochia chilensis Aristolochic Acids during Spring.

In this communication, we report the springtime variation of the composition of aristolochic acids (AAs) in Aristolochia chilensis leaves and stems. The dominant AA in the leaves of all samples, which were collected between October and December, was AA-I (1), and its concentration varied between 212.6±3.8 and 145.6±1.2 mg/kg and decreased linearly. This decrease occurred in parallel with the increase in AA-Ia (5) concentration from 15.9±0.8 mg/kg at the beginning of October to 96.8±7.8 mg/kg in mid-December. Both acids are enzymatically related by methylation-demethylation reactions. Other AAs also showed important variations: AA-II (2) significantly increased in concentration, reaching a maximum in the first two weeks of November and subsequently decreasing in mid-December to approximately the October levels. The principal component in the AA mixture of the stems was also AA-I (1); similar to AA-II (2), its concentration increased beginning in October, peaked in the second week of November and subsequently decreased. The concentrations of AA-IIIa (6) and AA-IVa (7) in the leaves and stems varied throughout the study period, but no clear pattern was identified. Based on the variation of AAs in A. chilensis leaves and stems during the study period, the reduced contents of non-phenolic AAs and increased concentrations of phenolic AAs are likely associated with a decrease in this plant's toxicity during the spring.

Scaling the Andean Shilajit: A Novel Neuroprotective Agent for Alzheimer's Disease.

Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder without a cure, despite the enormous number of investigations and therapeutic approaches. AD is a consequence of microglial responses to "damage signals", such as aggregated tau oligomers, which trigger a neuro-inflammatory reaction, promoting the misfolding of cytoskeleton structure. Since AD is the most prevalent cause of dementia in the elderly (>60 years old), new treatments are essential to improve the well-being of affected subjects. The pharmaceutical industry has not developed new drugs with efficacy for controlling AD. In this context, major attention has been given to nutraceuticals and novel bioactive compounds, such as molecules from the Andean Shilajit (AnSh), obtained from the Andes of Chile. Primary cultures of rat hippocampal neurons and mouse neuroblastoma cells were evaluated to examine the functional and neuroprotective role of different AnSh fractions. Our findings show that AnSh fractions increase the number and length of neuronal processes at a differential dose. All fractions were viable in neurons. The AnSh fractions inhibit tau self-aggregation after 10 days of treatment. Finally, we identified two candidate molecules in M3 fractions assayed by UPLC/MS. Our research points to a novel AnSh-derived fraction that is helpful in AD. Intensive work toward elucidation of the molecular mechanisms is being carried out. AnSh is an alternative for AD treatment or as a coadjuvant for an effective treatment.

Transcriptomic analyses reveal increased expression of dioxygenases, monooxygenases, and other metabolizing enzymes involved in anthracene degradation in the marine alga Ulva lactuca.

To analyze the mechanisms involved in anthracene (ANT) degradation in the marine alga Ulva lactuca, total RNA was obtained from the alga cultivated without ANT and with 5 µM of ANT for 24 h, and transcriptomic analyses were performed. A de novo transcriptome was assembled, transcripts differentially expressed were selected, and those overexpressed were identified. Overexpressed transcripts potentially involved in ANT degradation were: one aromatic ring dioxygenase, three 2-oxoglutarate Fe (II) dioxygenases (2-OGDOs), and three dienelactone hydrolases that may account for anthraquinone, phthalic anhydride, salicylic acid, and phthalic acid production (pathway 1). In addition, two flavin adenine dinucleotide (FAD)-dependent monooxygenases, four cytP450 monooxygenases, two epoxide hydrolase, one hydroxyphenylpyruvic acid dioxygenase (HPPDO), and two homogentisic acid dioxygenases (HGDOs) were identified that may also participate in ANT degradation (pathway 2). Moreover, an alkane monooxygenase (alkB), two alcohol dehydrogenases, and three aldehyde dehydrogenases were identified, which may participate in linear hydrocarbon degradation (pathway 3). Furthermore, the level of transcripts encoding some of mentioned enzymes were quantified by qRT-PCR are in the alga cultivated with 5 µM of ANT for 0-48 h, and those more increased were 2-OGDO, HGDO, and alkB monooxygenase. Thus, at least three pathways for ANT and linear hydrocarbons degradation may be existed in U. lactuca. In addition, ANT metabolites were analyzed by gas chromatography and mass spectrometry (GC-MS), allowing the identification of anthraquinone, phthalic anhydride, salicylic acid, and phthalic acid, thus validating the pathway 1.

Origanum vulgare L. essential oil inhibits virulence patterns of Candida spp. and potentiates the effects of fluconazole and nystatin in vitro.

BACKGROUND: Recurrence and resistance of Candida spp. infections is associated with the ability of these microorganisms to present several virulence patterns such as morphogenesis, adhesion, and biofilm formation. In the search for agents with antivirulence activity, essential oils could represent a strategy to act against biofilms and to potentiate antifungal drugs. OBJECTIVE: To evaluate the antivirulence effect of Origanum vulgare L. essential oil (O-EO) against Candida spp. and to potentiate the effect of fluconazole and nystatin. METHODS: The effect of O-EO was evaluated on ATCC reference strains of C. albicans and non-albicans Candida species. Minimum inhibitory concentration (MIC) was determined through broth microdilution assay. Adhesion to microplates was determined by crystal violet (CV) assay. An adapted scratch assay in 24-well was used to determine the effect of essential oil on biofilms proliferation. Viability of biofilms was evaluated by MTT reduction assay and through a checkerboard assay we determined if O-EO could act synergistically with fluconazole and nystatin. RESULTS: MIC for C. albicans ATCC-90029 and ATCC-10231 was 0.01 mg/L and 0.97 mg/L, respectively. For non-albicans Candida strains MIC values were 2.6 mg/L for C. dubliniensis ATCC-CD36 and 5.3 mg/L for C. krusei ATCC-6258. By using these concentrations, O-EO inhibited morphogenesis, adhesion, and proliferation at least by 50% for the strains assayed. In formed biofilms O-EO decreased viability in ATCC 90029 and ATCC 10231 strains (IC50 7.4 and 2.8 mg/L respectively). Finally, we show that O-EO interacted synergistically with fluconazole and nystatin. CONCLUSIONS: This study demonstrate that O-EO could be considered to improve the antifungal treatment against Candida spp.

Activity of Adesmia boronioides resinous exudate against phytopathogenic bacteria.

Resinous exudate obtained from the aerial parts of Adesmia boronioides Hook.f. were evaluated to determine anti-phytopathogenic effects. Briefly, resinous exudate was obtained by dipping fresh plant material in dichloromethane; chemical composition was determined by GC-MS; and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated against four phytopathogenic bacteria. Resinous exudate yield was 8.5% (resin/fresh plant), of which esquel-6-en-9-one (14.25%), esquel-7-en-9-one (5.86%), and veratric acid (2.59%) were the effective antibacterial compounds. Tested against Pectobacterium carotovorum subsp. carotovora, Erwinia amylovora, Bacillus subtilis, and Pseudomonas syringae, MICs and MBCs ranged from 16 to 128 µg/mL and 32-256 µg/mL, respectively. These results provide initial evidence that resinous bush A. boronioides is a new and alternative source of substances with agricultural interest.

Volatile Compound Screening Using HS-SPME-GC/MS on Saccharomyces eubayanus Strains under Low-Temperature Pilsner Wort Fermentation.

The recent isolation of the yeast Saccharomyces eubayanus has opened new avenues in the brewing industry. Recent studies characterized the production of volatile compounds in a handful set of isolates, utilizing a limited set of internal standards, representing insufficient evidence into the ability of the species to produce new and diverse aromas in beer. Using Headspace solid-phase microextraction followed by gas chromatography-mass spectrometry (HS-SPME-GC-MS), we characterized for the first time the production of volatile compounds in 10 wild strains under fermentative brewing conditions and compared them to a commercial lager yeast. S. eubayanus produces a higher number of volatile compounds compared to lager yeast, including acetate and ethyl esters, together with higher alcohols and phenols. Many of the compounds identified in S. eubayanus are related to fruit and floral flavors, which were absent in the commercial lager yeast ferment. Interestingly, we found a significant strain × temperature interaction, in terms of the profiles of volatile compounds, where some strains produced significantly greater levels of esters and higher alcohols. In contrast, other isolates preferentially yielded phenols, depending on the fermentation temperature. This work demonstrates the profound fermentation product differences between different S. eubayanus strains, highlighting the enormous potential of this yeast to produce new styles of lager beers.

Influence of gelation on the retention of purple cactus pear extract in microencapsulated double emulsions.

A purple cactus pear (Opuntia ficus-indica) extract (CP) was encapsulated in double emulsions (DE) gelled with gelatin (DE-CP-G) and with gelatin and transglutaminase (DE-CP-GT), as well as in a DE with a liquid external aqueous phase (DE-CP), in order to study the retention of betanin as colorant agent. Both gelled DEs showed a predominantly elastic behavior, in contrast with DE-CP. The degradation rate constant of betanin was significantly higher in DE-CP-GT (90.2 x 10-3 days-1) than in DE-CP-G (11.0 x 10-3 days-1) and DE-CP (14.6 x 10-3 days-1) during cold-storage (4 °C). A shift towards yellow color was found in all the systems during cold-storage (4 °C) and after thermal treatment (70°C/30 min), especially in DE-CP-GT, denoting a higher degradation of betanin. Betalamic acid, cyclo-Dopa 5-O-ß-glucoside, 17-decarboxy-betanin and neobetanin were identified by UHPLC-MS/MS as degradation products of betanin.

Insecticidal activity of essential oils from native medicinal plants of Central Argentina against the house fly, Musca domestica (L.).

The insecticidal activity of nine essential oils (EOs) against the house fly (Musca domestica) was evaluated by placing flies in a screw-cap glass jar holding a piece of EO-treated cotton yarn. The dose necessary to kill 50% of flies (LC(50)) in 30 min was determined at 26 +/- 1 degrees C. The EOs showed LC(50) values ranging from 0.5 to 46.9 mg/dm(3). The EO from Minthostachys verticillata was the most potent insecticide (LC(50) = 0.5 mg/dm(3)) followed by EOs from Hedeoma multiflora (LC(50) = 1.3 mg/dm(3)) and Artemisia annua (LC(50) = 6.5 mg/dm(3)). The compositions of the nine EOs, obtained by hydrodistillation of medicinal herbs, were analyzed by gas chromatography/mass spectroscopy. These analyses showed that (4R)(+)-pulegone (69.70%), menthone (12.17%), and limonene (2.75%) were the principal components of M. verticillata EO. (4R)(+)-pulegone was also the main constituent (52.80%) of H. multiflora, while artemisia ketone (22.36%) and 1,8-cineole (16.67%) were the major constituents of A. annua EO. The terpene (4R)(+)-pulegone showed a lower toxicity (LC(50) = 1.7 mg/dm(3)) than M. verticillata or H. multiflora EOs. Dimethyl 2,2-dichlorovinyl phosphate, selected as a positive control, showed an LC(50) of 0.5 mg/dm(3). EOs from M. verticillata and H. multiflora show promise as natural insecticides against houseflies.

Efficacy of essential oils from edible plants as insecticides against the house fly, Musca domestica L.

The compositions of 12 essential oils (EOs) obtained by hydrodistillation of edible fruits and herbs were analyzed by gas chromatography/mass spectroscopy (GC/MS). The insecticidal activity of each oil against the house fly Musca domestica was evaluated by placing flies in a glass jar with a screw cap that held a piece of EO-treated cotton yarn. The dose necessary to kill 50% of flies (LC(50)) in 30 min was determined at 26 +/- 1 degrees C. Twelve EOs and 17 individual terpenes were assayed against M. domestica, showing LC(50) values ranging from 3.9 to 85.2 and from 3.3 to >100 mg/dm(3), respectively. EO from Citrus sinensis was the most potent insecticide (LC(50 )= 3.9 mg/dm(3)), followed by EOs from C. aurantium (LC(50 )= 4.8 mg/dm(3)) and Eucalyptus cinerea (LC(50 )= 5.5 mg/dm(3)). According to GC/MS analysis, limonene (92.47%), linalool (1.43%), and b-myrcene (0.88%) were the principal components of C. sinensis EO. Limonene was also the principal constituent (94.07%) of C. aurantium, while 1,8-cineole (56.86%) was the major constituent of E. cinerea EO. 1,8-Cineole was most active against M. domestica (LC(50 )= 3.3 mg/dm(3)), while (4R)(+)-limonene, was moderately active (LC(50 )= 6.2 mg/dm(3)). Dimethyl 2,2-dichlorovinyl phosphate (DDVP) selected as a positive control, showed an LC(50) of 0.5 mg/dm(3). EOs from C. sinensis, C. aurantium, and E. cinerea show promise as natural insecticides against houseflies.

Degradation of ampicillin antibiotic by electrochemical processes: evaluation of antimicrobial activity of treated water.

Ampicillin (AMP) is an antibiotic widely used in hospitals and veterinary clinics around the world for treating infections caused by bacteria. Therefore, it is common to find traces of this antibiotic in wastewater from these entities. In this work, we studied the mineralization of this antibiotic in solution as well as the elimination of its antimicrobial activity by comparing different electrochemical advanced oxidation processes (EAOPs), namely electro-oxidation with hydrogen peroxide (EO-H2O2), electro-Fenton (EF), and photo electro-Fenton (PEF). With PEF process, a high degradation, mineralization, and complete elimination of antimicrobial activity were achieved in 120-min electrolysis with high efficiency. In the PEF process, fast mineralization rate is caused by hydroxyl radicals (·OH) that are generated in the bulk, on the anode surface, by UV radiation, and most importantly, by the direct photolysis of complexes formed between Fe3+ and some organic intermediates. Moreover, some products and intermediates formed during the degradation of the antibiotic Ampicillin, such as inorganic ions, carboxylic acids, and aromatic compounds, were determined by photometric and chromatographic methods. An oxidation pathway is proposed for the complete conversion to CO2.

Lithraea caustic (Litre) Extract Promotes an Antitumor Response Against B16 Melanoma.

Melanoma immunotherapy, specifically the autotransplant of dendritic cells charged with tumors antigens, has shown promising results in clinical trials. The positive clinical effects of this therapy have been associated to increased Th17 response and delayed-type hypersensitivity (DTH) against to tumor antigens. Some synthetic compounds, such as diphenylcyclopropenone (DPCP), are capable of triggering a DTH response in cutaneous malignancies and also to induce clinically relevant effects against melanoma. In this work, we evaluated Litre extract (LExT), a standardized extract of a Chilean stinging plant, Lithraea caustic (Litre). As Litre plant is known to induce DTH, we used a murine B16 melanoma model to compare the topical and intratumor efficacy of LExT with synthetic DTH inducers (DPCP and 2,4-dinitrochlorobenzene [DNCB]). LExt contained mainly long chain catechols and sesquiterpenes. The intratumor injection of LExT induced a significant delay in tumor growth, similarly topical treatment of an established tumor with 0.1% LExT ointment induced a growth delay and even tumor regression in 15% of treated animals. No significant changes were observed on the T-cell populations associated to LExT treatment, and neither DNCB nor DPCP were capable to induce none of the LExT-induced antitumoral effects. Interestingly, our results indicate that LExT induces an antitumor response against melanoma in a mouse model and could bring a new -and affordable- treatment for melanoma in humans.

Effective removal of the antibiotic Nafcillin from water by combining the Photoelectro-Fenton process and Anaerobic Biological Digestion.

The elimination of the antibiotic Nafcillin (NAF), which is usually used in hospitals and veterinary clinics around the world, was assessed through a combination of three advanced electrochemical oxidation processes followed by anaerobic digestion process. In the first stage different electrochemical advanced oxidation processes (EAOPs) were used: electro-oxidation with hydrogen peroxide (EO-H2O2), electro-Fenton (EF) and Photo electro-Fenton (PEF). After PEF, almost complete and highly efficient degradation and elimination of NAF was achieved, with the concomitant elimination of the associated antimicrobial activity. The fast degradation rate produced by PEF is explained by the oxidative action of hydroxyl radicals (•OH) together with the direct UV photolysis of complexes formed between Fe3+ and some organic intermediates. Total removal of NAF occurs after 90min of electrolysis by PEF, with the generation of organic intermediates that remain in solution. However, when this post PEF process solution was treated with an anaerobic biological process, the intermediates generated in the electrochemical degradation of NAF were completely eliminated after 24h. The kinetic degradation of NAF as well as the identification/quantification of products and intermediates formed during the degradation of antibiotic, such as inorganic ions, carboxylic acids and aromatic compounds, were determined by chromatographic and photometric methods. Finally, an oxidation pathway is proposed for the complete conversion to CO2.

Treatment of winery wastewater by anodic oxidation using BDD electrode.

The effective removal of organics from winery wastewater was obtained in real residual effluents from the wine industry using anodic oxidation (AO). The effluent had an initial organic load of [COD]0 of 3490 mg L-1 equal to [TOC]0 of 1320 mg L-1. In addition, more than 40 organic compounds were identified by means of GC-MS. Different density currents as well as the addition of electrolytes were tested during electrolysis. The results show the decay of [COD]t by 63.6% when no support electrolyte was added, whereas almost total mineralization and disinfection was reached after adding of 50 mM of sodium sulfate and sodium chloride and applying higher density currents. The presence of sulfate and chloride in large concentration favors the production of oxidants such as hydroxyl radicals and active chlorine species that react with organics in solution. Moreover, the addition of a supporting electrolyte to industrial wastewater increases conductivity, reduces cell potential and therefore, decreases the energy consumption of the AO process.

Chemical Composition and Anti-phytopathogenic Activity of the Essential Oil of Beilschmiedia miersii.

Belschmiedia miersii (Gay) Kosterm. (Lauraceae) ("Belloto del Norte") is a little-studied tree endemic of the Central Zone of Chile. Hydrodistillation of leaves and stem bark of B. miersii yielded 0.2% essential oil. GC-MS analysis allowed identification of 31 components. The most abundant compounds were three phenylpropanoids: Sarisan (45.8%), eugenol methyl ether (27.7%) and safrole (5.8%). The oil of B. miersii showed high antioxidant content (TEAC: 750.8 ±9.6 µmol/100 g of essential oil). The anti-phytopathogenic activity was evaluated against pathogens of plants: Fungi (Botrytis cinerea, Gibberella fujikitroi and Phytophthora cinnamomi) and bacteria: (Erwinia carotovora, Pseudomonas syringae and Agrobacterium tumefaciens) . The oil showed anti- phytopathogenic activity against all tested bacteria and fungi, especially against A. tumefaciens (IC50= 5 µg / mL) and P. cinnamomi (IC50 = 200 µg /mL). This study demonstrates that the essential oil of B. iniersii has great potential for applications in food and agricultural industries.

Fate of Ingested Aristolactams from Aristolochia chilensis in Battus polydamas archidamas (Lepidoptera: Papilionidae).

We performed a sequestration study of aristolactams (ALs) from Aristolochia chilensis in Battus polydamas archidamas (Lepidoptera: Papilionidae) by examining the AL content of the plant, fifth instar larvae, osmeterial secretion, pupae, exuviae and feces. Aristolactam-I (AL-I) and aristolactam-II (AL-II) present in A. chilensis are sequestered by fifth instar larvae of B. polydamas archidamas. There is a preferential sequestration of AL-II, or a more efficient metabolization and excretion of AL-I, by the larva. No ALs were found in the osmeterial secretion, pupae and exuviae; in addition, little AL-I and no AL-II were found in larval frass. The two lactams, particularly AL-I, are extensively metabolized to other products in the larva. A reasonable hypothesis is that the ingested ALs are oxidized to their respective aristolochic acids.

Antifungal study of the resinous exudate and of meroterpenoids isolated from Psoralea glandulosa (Fabaceae).

ETHNOPHARMACOLOGICAL RELEVANCE: Psoralea glandulosa L. (Fabaceae) is a medicinal resinous shrub used in Chilean folk medicine as antiseptic in treatment of infections and skin diseases caused by bacteria and fungus. AIM OF THE STUDY: To evaluate the in vitro antifungal activity of the resin and the active components from P. glandulosa against clinical yeast isolates. MATERIALS AND METHODS: Active compounds were obtained of the resinous exudate from aerial parts of P. glandulosa. Eight species of yeast were exposed to the resin and two major compounds. Minimum inhibitory concentration (MIC(80)) was determined according to the standard broth microdilution method. RESULTS: Bakuchiol and 3-hydroxy-bakuchiol demonstrated potent activity with the MIC(80) ranging from 4 to >16 and 0.125 to 16 µg/mL, respectively. The resin had some degree of antifungal activity. CONCLUSIONS: The overall results provided important information for the potential application of the 3-hydroxy-bakuchiol from P. glandulosa in the therapy of serious infection and skin diseases caused by clinical yeast.

Insecticidal effect of Cryptocarya alba essential oil on the housefly, Musca domestica L / Efecto insecticida del aceite esencial de Cryptocarya alba en la mosca doméstica, Musca domestica L

The composition of the essential oil (EO) from Cryptocarya alba obtained by hydro distillation of fresh leaves was analyzed using gas chromatography (GC) and gas chromatography/mass spectrosmetry (GC/MS). The insecticidal effect of the oil on the house fly Musca domestica was evaluated by placing flies in a sealed glass jar containing a piece of EO-treated cotton yarn. The dose necessary to kill 50 percent of flies (LC50) in 0.5 and 1 h was determined at 26 +/- 1 °C. The essential oil from Cryptocarya alba showed significant insecticidal properties [33.56 (7.06-159.50) mg/dm3 (0.5 h) and 15.07 (5.29-42.91) mg/dm3 (1 h)]. According to GC and GC/MS analysis a total of 38 compounds were identified. The composition of the Cryptocarya alba essential oil reported in this study is different to that reported in other publications with 4-terpineol (17.48 percent) ; 4- (3,3-dimethyl-but-1-ynyl) -4-hydroxy-2,6,6-trimethylcyclohex-2-enone (12.84 percent); 1,8-cineole (7.90 percent); p-cymene (7.11 percent) and sabinene (6.80 percent), accounting for 52.13 percent of the EO. The EO from Cryptocarya alba appears promising as a natural insecticide against houseflies.

La composición del aceite esencial (AE), obtenido por hidrodestilación de hojas frescas de Cryptocarya alba se analizó mediante cromatografía de gases (CG) y cromatografía de gases/espectrometría de masas (CG/EM). La actividad insecticida del aceite contra la mosca doméstica, Musca domestica se evaluó colocando las moscas en un frasco de vidrio sellado con un trozo de hilo de algodón tratado con diferentes cantidades de AE. La dosis necesaria para matar el 50 por ciento de las moscas (LC50) en 0,5 y 1 hora se determinó a 26 +/- 1 oC. El aceite esencial de Cryptocarya alba mostró un buen efecto insecticida [33,56 (7,06-159,50) mg/dm3 (0,5 h) and 15,07 (5,29-42,91) mg/dm3 (1 h)]. La composición del aceite esencial de Cryptocarya alba encontrada en este trabajo es diferente al informado en otras publicaciones, con 4-terpineol (17,48 por ciento); 4-(3,3-dimetil-but-1-inil)-4-hidroxi-2,6,6-trimetilciclohex-2-enona (12.84 por ciento); 1,8-cineole (7,90 por ciento); p-cimeno (7,11 por ciento) y sabineno (6,80 por ciento), lo que representa el 52.13 por ciento del AE. El AE de Cryptocarya alba parece prometedor como un insecticida natural contra la mosca doméstica.

Phenolic aristolactams from leaves and stems of Aristolochia chilensis / Aristolactamas fenólicas de hojas y tallos de Aristolochia chilensis

Three phenolic aristolactams, aristolactam AII (3), velutinam (4) and piperolactam A (5), were identified from the leaves and stems of Aristolochia chilensis Bridges ex Lindl. The structures of these compounds were elucidated using a combination of HPLC-DAD, GC-MS and NMR experiments.

Tres aristolactamas fenólicas aristolactama AII(3), velutinam(4) y piperolactama A(5), se identificaron en hojas y tallos de Aristolochia chilensis Bridges ex Lindl. Las estructuras de estos compuestos se determinaron por combinación de CLAE-DAD, CG-EM y experimentos de RMN.

Insecticidal properties of Heliotropium stenophyllum essentialoil on the House fly, Musca domestica L / Propiedades insecticidas del aceite esencial de Heliotropium stenophyllum en la mosca doméstica, Musca domestica L

The composition of the essential oil (EO) obtained by hydro distillation from dry leaves of Heliotropium stenophyllum (Heliotropiaceae) was analyzed using gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The insecticidal activity of the oil against the house fly Musca domestica was evaluated and the dose necessary to kill 50 percent of flies (LC50) in 2 h was determined at 25 +/- 1 °C. The essential oil from Heliotropium stenophyllum showed potent insecticidal properties (LC50 = 1.09 mg/dm3) in comparison with other essential oils, in which at shorter times, the same bio-assay was used. According to GC and GC/MS analysis, junenol (19.08 percent); longiborneol (9.34 percent); (E, Z)-geranyl linalool (6.81 percent); selina-3,11-dien-6-alpha-ol (6.70 percent); alpha-cedrene epoxide (6.60 percent); heliofolen-12-al D (6.23 percent) and beta-epi-bisabolol (4.83 percent were the principal components of the EO. The Heliotropium stenophyllum essential oil, made up exclusively of sesquiterpenes, showed a composition very different from the EOs of the other species of Heliotropium, studied, and present a great potential as a natural insecticide against houseflies.

La composición del aceite esencial (AE) obtenido por hidrodestilación de hojas secas de Heliotropium stenophyllum (Heliotropiaceae) se analizó mediante cromatografía de gases (CG) y cromatografía de gases/espectrometría de masas (CG/EM). La actividad insecticida del aceite contra la mosca doméstica Musca domestica se evaluó y la dosis necesaria para matar el 50 por ciento de las moscas (LC50) en 2 h se determinó a 25 +/- 1 ºC. El aceite esencial de Heliotropium stenophyllum mostró potentes propiedades insecticidas (LC50 = 1,09 mg/dm3) en comparación con otros aceites esenciales, en el que en tiempos más cortos, se utilizó el mismo bio-ensayo. De acuerdo con los análisis de CG y CG/EM, junenol (19,08 por ciento); longiborneol (9,34 por ciento), (E, Z)-geranil linalool (6,81 por ciento); selina-3,11-dien-6-alfa-ol (6,70 por ciento); epoxido de alfa-cedreno (6,60 por ciento); heliofolen-12-al D (6,23 por ciento) y beta-epi-bisabolol (4,83 por ciento) fueron los componentes principales identificados en el AE. El aceite esencial de Heliotropium stenophyllum, formado exclusivamente por sesquiterpenos, mostró una composición muy diferente al de los AEs de otras especies de Heliotropium, estudiadas, y muestra un gran potencial como insecticida contra la moscas doméstica.